The images in the product description shows the height as 18mm from the bottom of the knob to the top of the knurling - not to the top of the knob. In fact, the correct dimension for knurling portion is ~13.5mm. The knob is about 18mm to the very top. The diameter is correct as illustrated: ~18mm.The product was nicely packages as a vacuum wrap on a cardboard card - protected but with no wasted boxes, etc., and it included the Allen key and a pick. I'm sure they are fine knobs, but I bough thee specifically because of the illustrated dimensions.